3 files changed, 97 insertions(+), 5 deletions(-)

M spec/sparse/vector_spec.cr
M spec/spec_helper.cr
M src/sparse/vector.cr

@@ 91,4 91,86 @@ describe Sparse::Vector do
       v.extract_element(43).should be_nil
     end
   end
+
+  describe "#set_element" do
+    it "inserts at the provided index" do
+      context "populated" do
+        v = Sparse::Vector(Int32, 10000).random 1000
+        v.set_element 42, 1729
+        v.extract_element(42).should eq(1729)
+      end
+
+      context "empty" do
+        v = Sparse::Vector(Int32, 10000).new
+        v.set_element 42, 1729
+        v.extract_element(42).should eq(1729)
+      end
+    end
+
+    it "overwrites an existing value if present" do
+      v = Sparse::Vector(Int32, 10000).new
+      v.set_element 42, 1729
+      v.set_element 42, 1
+      v.extract_element(42).should eq(1)
+    end
+
+    it "raises when out of bounds" do
+      v = Sparse::Vector(Int32, 100).new
+      expect_raises(IndexError) do
+        v.set_element 1000, 42
+      end
+    end
+  end
+
+  describe "#remove_element" do
+    it "drops the element at the specified index" do
+      v = Sparse::Vector(Int32, 100).new
+      v.set_element 42, 1729
+      v.remove_element(42).should eq(1729)
+      v.extract_element(0).should be_nil
+    end
+
+    it "ignore unset element indicies" do
+      v = Sparse::Vector(Int32, 100).new
+      v.remove_element(42).should be_nil
+    end
+
+    it "raises when out of bounds" do
+      v = Sparse::Vector(Int32, 100).new
+      expect_raises(IndexError) do
+        v.remove_element 1000
+      end
+    end
+  end
+
+  describe "#extract_element" do
+    it "returns to the element at the specified index" do
+      v = Sparse::Vector(Int32, 100).new
+      v.set_element 42, 1729
+      v.extract_element(42).should eq(1729)
+    end
+
+    it "returns nil if the element does not exist" do
+      v = Sparse::Vector(Int32, 100).new
+      v.extract_element(42).should be_nil
+    end
+
+    it "raises when out of bounds" do
+      v = Sparse::Vector(Int32, 100).new
+      expect_raises(IndexError) do
+        v.extract_element 1000
+      end
+    end
+  end
+
+  describe "#extract_tuples" do
+    it "provides the underlying idx, val arrays" do
+      idx = Sparse::Spec::Random.rand(Array(UInt64), 1000, max: 10000, sorted: true)
+      val = Sparse::Spec::Random.rand(Array(UInt8), 1000)
+      vec = Sparse::Vector(UInt8, 10000).new idx, val
+      idx2, val2 = vec.extract_tuples
+      idx2.should be(idx)
+      val2.should be(val)
+    end
+  end
 end

@@ 11,6 11,17 @@ module Sparse::Spec::Random
     SOURCE.rand type
   end
 
+  def self.rand(max)
+    SOURCE.rand max
+  end
+
+  # OPTIMIZE: build in O(n) when specs get slow. This is simple for now.
+  def self.rand(klass : Array(T).class, size, max = T::MAX, sorted = false) : Array(T) forall T
+    arr = Array.new(size) { rand T.new(max) }
+    arr.sort! if sorted
+    arr
+  end
+
   ::Spec.before_suite do
     puts "Running with random seed: #{SEED}"
   end


@@ 18,9 29,8 @@ end
 
 struct Sparse::Vector(T, N)
   def self.random(nvals = 1000)
-    # OPTIMIZE: build in O(n) specs get slow. This is simple for now.
-    idx = Array.new(nvals) { Sparse::Spec::Random.rand UInt64 }.sort!
-    val = Array.new(nvals) { Sparse::Spec::Random.rand T }
+    idx = Spec::Random.rand(Array(UInt64), nvals, max: N, sorted: true)
+    val = Spec::Random.rand(Array(T), nvals)
     new idx, val
   end
 end

@@ 113,9 113,9 @@ module Sparse
     end
 
     # Extract one element of *self* into a scalar.
-    @[AlwaysInline]
     def extract_element(index : Int) : T?
-      fetch(index) { nil }
+      check_index_out_of_bounds index
+      unsafe_fetch index
     end
 
     # Extract all elements with values assigned.